Semiautomatic tuner device for radio apparatus and the like



June 14, 1949.-

R. w. may 2,472,979 snmmuwom'rxc TUNER D VICE FOR mnxo APPARATUS AND THE LIKE Filed May 23-, 1946 5 Sheets-Sheet 1 K/CHARD h/MAY J I INVENTOR ATTORNEY I June 14, 1949. 2,472,919

- R. w. MAY SEMIAUTOMATIC TUNER DEVICE FOR RADIO APPARATUS AND THE LIKE Filed May 23, 1946 5 Sheets-Sheet 2 R/cHA/w M MAY INVENTOR ATTORNEY June 14, 1949. R. w. MAY

SEMIAUTOMATIC TUNER DEVICE FOR RADIO APPARATUS AND THE LIKE Filed May 23, 1946 5 Sheets-Sheet 3 K/(HA RD M/VA Y INVENTOR ATTORNEY June 14, 1949. R. w. MAY 2,472,979

' SEMIAUTOMATIC TUNER DEVICE FOR RADIO APPARATUS AND THE LIKE FiledMay 23, 1946 5 Sheets-Sheet 4 7 June 14, 1949.

MAY 2,472,979

R. W. SEMIAU'I'OMATIC TUNER DEVICE FOR RADIO APPARATUS AND THE LIKE Filed May 23, 1946 5 Sheets-Sheet 5 a .Q. I j fi/tHA/w M/VAY INVENTQR BY AM ATTORNEY Patented June 14, 1949 UNITED STATES ATE-NT OFFICE SEMIAUTOMATIC TUNER DEVICE FOR more APPARATUS AND THE LIKE Richard W. May, Cedar Rapids, Iowa, assignor to Collins Radio Company, Cedar Rapids, Iowa, a

corporation of Iowa.

This inventionrelates to semi-automatic controls for rotatable shafts, and more particularly to a device forselectively operatinga control .or tuning shaft for radioapparatus and the like -To facilitate'tuning of radio apparatus, such for example as a radiotransmitter, it is desirable ii'rsome cases to have a semi-automatic device whichactually turns the control or tuning shaft to a predetermined position even though the radio apparatus is equipped .with -conventional manual dials. With such manual dials, it is not possible in -all-cases to tune the equipment by a single ad- .iustment of the tuning dial. In most cases, the dial is either'turned too far or too-little on the first movement, necessitating a gradual hunting torthe exact settingcorresponding to a particular frequency. If the radioapparatus is of the type having several tuning dials, there is considerable time consumed beiore all the dials are set on exactly the right points. In accordance with the presentinvention, each manual tuning dial is provided with a semi-automatic actuating mechanism so that merely by turning the dial manually to a given one of a'zseries of settings;-the subsequent actuation ofthe tuning shafts is accomplished automatically and with a maximum of accuracy in the final setting. f

Accordingly, it is aprincipal object of this invention to provide a compact device of simplified construction. for. semi-automatic tuning radio apparatus.

.Another object of the invention is to provide a device for selectively adjusting radio apparatus and the like, which device is motor driven and is arranged to stop the tuning shaft in any desired angular position corresponding to that of-a manually' operable calibrated dial. J It is a further object of this inventionto provide a shaft control mechanism of the type employing-a series of presettable stop rings and -cooperating selector'pawls in conjunction With a compact arrangement for instantaneously starting the driving motor when the usuafm'a'nu'al tuning 'dialis first movecl'to a newsetting, and an automatically opening the motor circuit when a'sto'p ring is stopped by a selected pawl.

:A feature of the invention relates to a shaft control mechanism of the type employing a series of presettable stop rings and cooperating selector pawls wherein each pawl is provided with spring means cons. cted thereto so as toexerta continforce'on-the pawl in a direction tendi'ng 'to bring it into locking engagement with its 00- or ting stop ring. 1

:rAncther feature relates to the simplified mechemical arrangementzand;,electrical circuit controls associated with a tuning dial device of the typhaving a series of presettable stop rings and cooperating selector pawls.

Another.features-relates to animproved stop rings-controlsassembly having means to facilitate the presetting .of the individual rings of. the assembly.

still further "feature relates :to the novel organization, arrangement and relative interconnection of'partswhich cooperate to provide an improved semi-automatic tuningdevice for radio transmitters andsthelike. 1

-*-Other features and: advantages not specifically enumerated vwill be apparent after. a considerationof-the following detailed descriptions and the appendedsclaims. 'In -the drawingwhichrepresents a preferred embodiment,

-Fig. 1 'is-a side view :of a radio tuning control device embodying the inventive features. Fig. 2- is a sectional view along the line 2 2 of Fig: l yiewedin the direction of the arrows. --Fig. 2-A is a sectional View of Fig. 1, takenalong the-line-zAa2A -thereof.

Fig- 3 is a view of the device as seen from the opposite side to that shownin Fig. 1.

'i' FigrAisua sectional viewsimilar to Fig. 3, but takemalong the line 4J-4 ofFig. 2A. 9

1"Figz-5'isafront elevationalzview of Fig. 1 with partof .the supportingstructure broken away to show. certain interiorparts more clearly.

..:Fig. 6 is a plan view ofone of the stop ring drum spacers accordingto the invention.

Fig. 7 is an-enlarged viewof part of the stop ring drum as'sembly' explanatory of the action di 'thespacers 'ofFig; '6.

-fi-Fig 8 isja composite m echanicaland electrical circuit diagram explanatory of the operation of thedevice according to' th e invention.

fFig; 91s a composite mechanical and electrical circuit diagram of a modification of the invention. There 'is shown in Figr -l, a control shaft l, which may be the rotatable shaft to Whichis attachedthe rotor plates 2 of a tuning condenser 3, such-as conventionally used in radio equipment. In 'certain kinds of radio apparatus, because of the sizeorweigh't of: the tuning elements and associated parts, it; is necessary '01" desirable to provide 'themwitl't motlve power from an electric motor; TAt'the' same timefit is necessary to insure that'thertuni'n'g control .sl'iaft be accurately oriented in its desired angular position. The-prob le'ni is ol even greater importance where the radio equipment} such -for example as a large radio transmitter, has a considerable number of individually settable tuning controls. In accordance with the present invention, these controls are each settable in a semi-automatic manner under control of a simple and easily calibrated knob or dial. With this arrangement, it is merely necessary to turn each calibrated knob manually to the desired setting, and the device thereafter acts automatically to rotate the corresponding tuning control shaft until the selected setting is reached.

The tuning control device according to the invention is arranged as a self-contained unit mounted between the front and rear end plates l and II, which are rigidly united in spaced relation by the top plate l2 and bottom plate l3. The shaft l6 which is adapted to control the tuning shaft l is mounted in suitable bearings in end plates It and H. A cylindrical stop ring drum I is keyed or otherwise fastened to shaft I4, so as to be rotatable therewith. A series of tenivsimilar stop rings Ilia-457' are mounted around ."drum l5 and capable of being individually adjusted around this drum to effect their respective presettings, whereupon they can then be locked to the drum so as to rotate as a unit therewith. The locking and unlocking of ringsJGd-Afij is controlled by thumb screw l'l. Gear l8 is appropriately coupled to an electrical: drive motor'33 (Fig. 5) and causes rotation of'shaft l4 through slip clutch l9. Shaft M. can be turned manually independently of motor 33 by knob 20.

The stop rings Mia-45a are so designed that whenxfixed in selected preset position with relation to shaft 14, they cooperate with the respective sele'ctingpawls 2 [CL-2l7' which are pivotally mounted on pawl shaft 22. A selected pawl: moves into locking engagement with its respective stop ring only when shaft Id is driven by motor-33'to a predetermined angular position which in turn is determined by the setting of the manual knob Locking engagement between a'pawl and its respective stop ring is accomplishe'dwhen the stop lug 2311-237 of a selected pawl enters the associated slot Mrs-24 i of the stop rings.

Associated with the pawls is a cam barrel comprising a series of ten cams flit-#259, keyed or otherwise fastened to camshaft 26, so as to rotate as a unit therewith in accordance with the manualnsetting of the calibrated knob 21. Each cam Era- 257 has a slot or recess 2811-487 respectively which receives the riding portion of the coacting pawl, these riding portions being designated E o- 297. Each pawl is biased by a corresponding one of a series of tension springs 3ila,-3ll7' to rotate the pawls counter-clockwise as seen in Figs. 2 and 2A. The recesses 2841-287 in the peripheries of cams fizz-257' respectively are equally spaced and so arranged as to form a helical path around the cam drum assembly. The helical arrangement of the cam slots Zair -28y allows all of the pawls, except the selected one, to ride on the peripheries of their respective coasting cams. When the riding portion of the selected pawl engages the preset recess of its coacting cam, the stop lug of that pawl .rides on the periphery of its cooperating stop ring until shaft Hi reaches its selected angular position, whereupon the stop lug enters the stop ring slot and causes tuning shaft M to stopinstantaneously, whereupon the clutch l9 slips.

Referring more particularly to Figs. 2 and 2A, let it be assumed that it is desired to tune the apparatus to a frequency corresponding to that represented by engagement of pawl Zlg' with its associated stop ring I67. In Fig, 2, the shaft M is shown in such a position that the riding portion 297' rides on the periphery of cam 25;! which allows stop lug 239' of this same pawl to clear the periphery of the associated stop ring 153.. Springs slick-309 are; anchored to any suitable support 36, there being one such spring for Leach pawl tending to urge it in a counter-clockwise direction as seen in Figs. 2 and 2A. To

.effecta new tuned position of shaft 14, dial knob 21 is now manually turned in either direction,

for-example counter-clockwise causing counterclockwise rotation of the cam barrel. The dial 27a is calibrated inpositions each corresponding respectively-to a slot in one of the cams. Consequently, when recess 287' corresponding to the .manualrsetting of knob 27 is directly beneath riding portion 297', the associated spring 307 causes the portioni j to enter recess 281i and allows the corresponding stop lug 237' to ride .on the'periphery. of stop-ring [67. As soon as any pawl rotates clockwise as above described, it closes a power circuit through the driving motor 33.- as-wilLbe' described in detail in connection with Fig. 8; Shaft I4 is thereupon automatically rotated by motor 33 and continues to rotate until slotZ ly' inthe periphery of ring 16y comes into registry with stop lug 231'. Spring 307' thereupon-causes the stoplug to enter the slot 247 and causesshaft Hi to be stopped instantaneously. .The. arrangement is such that as soon as apawlrotates counter-clockwise sufficiently to allow itsstop lug to enter the stop ring slot, the motor circuit is opened as will be described in connection with Fig. 8.

...If it isdesired-to retune shaft 14 to a differentsetting; it is accomplished in the same manner;- as 1 above-described; namely, by manually turning-knob 21 ineither. direction to the new positionwhichmechanically forces pawl 2h to rotatein a-clockwise direction to cause disengagement of the stop lug 235) from the slot 243i. The shape of .the lugs-23a123:i and the shape of the lugs-129M499- are such as to permit disengagement of the previously set pawl as soon as thefknob fl is manually turned, this shape being fully'set forth and claimed in application Serial No. 515,250, filed December 22, 1943.

When shaft 14 is stopped by engagement of a stop ring slot with its associated preset pawl, slip-clutch l9;throughwhich gear 18 drives shaft it, allows gear 8 to turn relative to the'shafts. When shaft 26' is manually-turned by knob 21 as above described, the previously set pawl is disengaged from its stop ring slot allowing shaft M to rotate. Clutch I9 is preferably of the type described in detail in the application of Arthur A. Collins; Serial'No, 483,899, filed April 21, 1943, nowsPatent Number 2,409,192. This clutch is designed sothat it serves to limit the torque delivered tothe stop ring drum l5, while permitting therotation of the drive motor after the stopiring drum has been selectively stopped. Its transmissible torque is substantially entirely a function of the spring (not shown) and is independent. of varying inter-surface coeflicients. While the drawing shows ten stop rings and ten respective pawls, each actuated by a corresponding cam, it is clear that a greater or less number may be employed dependinguponthe number ofituning'positions of shaft 14.

Fig. 3 shows more clearly the means for driving shaft 14; The master shaft 32- driven by a suitable motor 33 carries a worm gear 34, which meshes with gear l8. Each of the selector pawls 2la2|7' is aligned with its respective stop ring and selector cam, the pawls being suitably spaced axially. by spacer discs 35a-35i. The two end collars 36 are keyed to shaft 22, so as to prevent axial movement of the cams on that shaft once they are assembled in the proper position thereon.

As shown more clearly in Fig. 4, stop rings Ida-I69 are separated by intermediate spacer discs 3111-311 respectively. The drum I5 is made up of a series of annular segments l5a-l57'. equal in number to the number of stop rings. These drum segments together with the intervening discs 3l'a -31i are rigidly clamped to form a unitary barrel which is keyed or otherwise anchored to shaft l4. The end member I57 may be suitably keyed to shaft M so as to force the pile-up of segments rigidly aga nst the face plate of clutch I9, which in turn is rigidly backed by nut 38 threaded on shaft I l. The outer margin of each of the drum segments l5al 5y is of reduced transverse thickness:with respect to .the transverse thickness of the stop rings, to allow limited axial movement of the stop rings and of the outer margins of the spacer discs, which movement is necessaryin locking and unlocking the relative positions of the stop rings relative to the shaft [4. It will be seen from Fig. 4 that the spacer discs 3'la-3li are rigidly clamped as a unit with the drum segments, by the shiftable annular clamping member 39, and the outer diameter of each spacer is greater than the outer diameter of the drum segments so as to provide a radially extending and springy margin which lies between each pair of adjacent stop rings. These spacer discs are also designed so as to facilitate angular presetting of the stop rings relative to shaft M when the stop rings are unlocked. One of these spacers is shown in detail in Fig. 6 and, in accordance with the invention, they provide clamping surfaces between the adjacent stop rings, while allowing those rings to be rotated manually with a minimum of frictional drag when the rings are unlocked. As shown more clearly in the enlarged View of Fig. 7, the cam drum segments [Ea-I57 are slightly thicker than the corresponding stop rings. Consequently, when the stop ring assembly is clamped, it-causes the outer flexible margins of the spacer discs 31CL-3'! to be deflected toward the right. Upon release of the clamping pressure, these margins spring backtowards the left thus slightly separating the stop rings by a positive separating force. By this arrangement, it is possible to unlock the rings and to rotate any ring to its preset position without affecting the previously. preset position of any other ring, and shaft I l-can be manually rotated by knob 21 independently of clutch 1-9. This therefore reduces greatly the frictional load on the stop rings during their manual pre-' setting. Nut 38, and annular clamping member 39. provide means for clamping the stop rings lea-I69 and spacer discs 3la,3li as a rigid unit on the drum I5. Thumb screw I! which cooperates with looking stud 4!! is threaded into shaft [4 as shown in Fig. 4, consequently rotation of screw I? causes axial movement of stud Ml, the direction 'of rotation vof screw ll determining whether the stop rings are locked or unlocked. The actual locking and unlocking of :the stop rings is accomplished by the .axial movement of the member 39-.which -is carried bya bar 4 I; passing through shaft :14 and actuated by the movement of lockingstud-M.{When in the unlocked condition, face 42 of member 39, rests against stop shoulder d3. If thumb screw l1 isrotated in a clockwise direction, member 39 moves to the right (Fig. 4) and the clamping is increased until all 5 stop rings are locked to the shaft Id. The pitch of the threads on looking stud M is so chosen that there is no tendency to rotate shaft M; during either the looking or unlocking operation. In other words, the torque required to overcome the friction between the stop rings and their associated intermediate spacers is always greater than the torque required to rotate the locking stud 49. In order that friction be reduced to a minimum and shaft M be accurately positioned, it is mounted onball bearings 4:3 and 45 in plates iii and M respectively.

The cams 25a25y' are fixedly clamped to the cam shaft 26 by the force of nut 46 against sleeve 47 and shoulder portion 48 on shaft 26. Since shaft 26 carrying cams flirt-25y is manually rotated by manipulation of dial 2 1, frictional drag and wear are not factors of paramount importance and simple journal bearings are used. These bearings may be formed by extruding a portion of the plates H3 and H.

As shown more clearly in Fig. 5 and as schematically illustrated in Fig. 8, each of the selector pawls has a downwardly depending lug 5! having a slot 52. Consequently, all the slots 52 are in alignment in a direction parallel to the shaft M. Extending through the aligned slots 52 is a bail member 53, the position of which is determined by the position of the selector pawls. Attached to one end of the bail 53 is a downwardly depending insulator arm 54, which is adapted to engage the movable contact 55 of a switch 56. The movable contact 56 cooperates with a corresponding fixed contact 5?, the contacts 55 and 57 when in engagement connecting the power supply such as the battery 58 in circuit with the armature of motor 33 and the field winding 59 thereof. The switch tit may be suitably mounted on the plate l3 as shown in Fig. 5 and the arm 54 may pass through a suitable guide at also attached to this 45 plate it. Since the drum 5-? is of the one-way motion type in the sense that the motor 33 drives the said drum Iii in only one direction, it is not necessary to provide any reversing control circuit for the motor. It will be noted that when any given pawl rotates counterclockwise (Figs. 5 and 8) to selective stopping position wherein the lug 23 fully registers with the slot in the associated stop ring, the arm is moved downwardly as a result of the tension of the pawl spring 36, caus- 55 ing the contacts 55 and 5'5 to open thus opening the motor power supply. It will also be observed that so long as the pawls are riding on the cams and so long as the lugs 23 are not in registry with the cooperating stop ring slots, the arm 55 is held 60 in a raised position thus maintaining the abovedescrihed power circuit for the motor closed. It will also be noted that immediately shaft 26 is manually rotated to start a new selection, the previously preset pawl is forced to rotate partially in a clockwise direction resulting a suflicientupward movement of the arm 5 to close the motor supply contacts 55 and 57. quently from there on, the motor 3-3 takes over and causes the rotation of the stop ring drum until the previously selected pawl registers with the appropriate stop ring slot.

If it is desired to change the set-up or tuning position of a stop ring on tuning shaft M,'-the dial 2'! is turnedto select the pawlassociated With that stop ring which jallows that pawl and stop,

Consering tocomexintolocking engagement thereby slipping the clutch IS. The driving motor 33 is then stopped and thumb screw ll rotated in a counter-clockwise direction placing the stop rings in the unlocked condition. Knob 20 is then rotated until the-tuning shaft I4 is in the desired angular position which causes the same angular displacement of the pawl engaged stop ring. Thumb xscrew H is then rotated in a clockwise direction until the stop rings are-caused to be in the locked condition. The device then stops or sets the shaft H- in this same angular position each time the same cam is selected. If desired, any number of new tuning positions or stop ring positionssmaybe accomplished by repeating the above procedure for each desired new position of the stop rings.

From' the foregoing "description, it will be clear that the entire sequence of operations required to tune shaft l toany desired position is controlled by the; simple manual turning of the knob 2! to the desired position. The turning of this knob notv only sets the-cam barrel to position a selected pawl, but also automatically closes the motor circuit instantaneously to cause the rotation of the stop ring drum. When the selected pawlfinally registers with the proper stop ring slot, the motor supply circuit is automatically opened and the shafts l-and MJare positively stopped. in the desiredposition. If desired an additional contactllil may be provided to control the circuit of a small electric lamp 62, so that when the arm 54 moved downwardly under control of any of the pawls to open the motor circuit, it simultaneously closes a circuit through the y lamp'fiz, thus giving a visual indication that the sequence of operations is complete.

In the foregoing description, the device is of the one-way type, that is to say the stop ring drum is designed to'rotate-in only one direction. In certain devices of this character, the stop ring drum is limited to asingle complete rotation and is arranged to undergo reversals of rotation until the :desired selective position is reached. For this purpose, it is necessary to employ a reversible motorifor the stop ring drum. At the same time, it is necessary to provide a limit switch arrangement so that when the stop ring drum has reached one limit of travel Without having completed the selected operation, its direction of ro tation' is automatically reversed until the desired selection is made. Such an arrangement is schematically shown in Fig. 9. 'For this purpose, in addition to the stop rings lid-463i, there is another stop ring its which carries a dog 63 which is adapted to operate the movable contact arm 64 of a suitable limit reversing switch65. This switch may be of any well-known snap action or toggle type so that when member 64 is engaged by dog 63, it is moved to one position or the other depending upon the previous direction of rotation of drum 15.

The parts of Fig. 9 bearing the same designation numerals as those of Fig. 8, function in the same manner. In Fig. 9, the motortt' has two separate directional control windings 66, 61, whose circuits are controlled by the limit-reversing switch 65'. In the particular position shown in Fig. 9, the. drum '5 has just reached the limit of its clockwise rotation and has operated arms 64 into engagement with contact 68 whichcom tacts therefore remain closed until the drum is about to reach the limit of its counter-clockwise rotation. If the present pawl is not' reached when the drum l5 reaches the-limit of its travel 11110118 direction, its rotation is therefore automatically reversed under control of switch 65 until the stop drum l5 reaches the selected position wherein .the preset pawl 2| registers with the appropriate slot in its cooperating stop ring.

While certain specific embodiments have been described herein, various changes and modifications may-be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A device for selectively setting a control shaft of radio apparatus and the like, comprising a. manually settable selector cam shaft having a' series of selector cams, a plurality of shift- I able: stop pawls one for each cam, a plurality of stop'rings arranged to be selectively stopped undercontrol of a selected one of said pawls, each of said pawls having a toe and heel portion with the heel portion in coacting engagement with a corresponding one of said cams and with its toe portionin coasting engagement with a corresponding one of said stop rings, a motor for rotating saidtstop rings and said control shaft as a unit, manual means for rotating said cam shaft to move a selected one of said pawls to a preliminary stopping position, a common switch operating bail mechanically linked to all said pawls, and a power supply circuit for said motor completed through said switch and which is automatically closed upon initial manual rotation of said cam shaft and which remains closed until said selected pawl is moved to its final stopping position where it is in selective stopping engagement with its associated stop ring said selected pawl thereupon moving said bail to open said motor circuit.

' 2. A device for setting a radio control shaft and the like, comprising a manually rotatable cam drum, a motor driven stop ring drum, a plurality of shiftable pawls cooperating with said cam drum and said stop ring drum to stop said shaft in a selective position, a motor for driving saidstop ring drum and said shaft, a power supply circuit for said motor, a switch for con-- trolling said power supply circuit, an operating bail common to all said pawls and operated thereby, and means controlled by said bail for operating said switch.

3. A device for selectively setting a radio control shaft and the like, comprising a manually rotatable selector cam drum, a motor driven stop ring drum, a plurality of shiftable pawls ranged to be selectively set under control of said cam drum, said pawls coacting with said cam drum and said stop ring drum to stop said shaft in a selective position, all of said pawls being linked to a common operating ball, a switch for controlling the power supply circuit of said motor, and means including said pawls for operating said switch in response to movement of said bail.

4. A device for selectively setting a radio control shaft and the like, comprising a series of selective pivoted pawls, each pawl having a selecting lug and a stopping lug, a motor driven stop drum cooperating with said stopping lugs, a manually rotatable cam drum cccperating with said selecting lugs, a motor for driving said motor driven drum, a switch for controlling the circuit of said motor, means responsive to' the initiation of rotation of the cam drum in one direction to move saidpawls in one direction and thereby to close the circuit of said motor, and means responsive to a predetermined setting of both 75 said drums to allow said pawls to move inanother direction and thereby to open the said motor circuit.

5. A device according to claim 4 in which said stop drum is arranged to undergo reverse rotations in arriving at its predetermined setting, and a limit reversing contol switch is provided and is operated in response to said drum reaching the limit of its travel in either direction for autounatically reversing the direction of rotation thereof until said setting is reached.

6. A device according to claim 4 in which said switch has an additional contact and an electric lamp is provided with a circuit controlled by said additional contact to cause said lamp to be lighted to produce a visual indication when the said setting is reached.

' RICHARD W. MAY.

REFERENCES CITED The following referemces are of record in the file of this patent:

Number Number UNITED STATES PATENTS Name Date Partz June 16, 1891 Sokolofi Aug. 12, 1930 Gersch Apr. 11, 1939 Prochnow Dec. 5, 1939 Claytor Feb. 11, 1941 Elliott Oct, 20, 1942 'Paessler Nov. 23, 1943 Korte et a] Nov. 30, 1943 Boterweg et a1 June 13, 1944 May June 26, 1945 May Mar. 19, 1946 FOREIGN PATENTS Country Date Great Britain Mar. 8, 1938 

